<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>WebSocket</title>
</head>
<body>
<form onsubmit="return false">
    <textarea name="message" style="height:300px;width:300px"></textarea>
    <input type="button" value="发生消息" onclick="send(this.form.message.value)">
    <textarea id="responseText" style="height: 300px;width:300px"></textarea>
    <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''">
</form>
<script>
    var socket;
    // 判断当前浏览器是否支持websocket
    if (window.WebSocket) {
        socket = new WebSocket("ws://localhost:7000/hello");
        // 相当于channelRead0，ev收到服务器端回送的消息
        socket.onmessage = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + ev.data;
        }
        // 相当于连接开启（感知到连接开启）
        socket.onopen = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = "连接开启了...";
        }
        // 相当于连接关闭（感知到连接关闭）
        socket.onclose = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n连接关闭了."
        }

        // 发送消息到服务器
        function send(message) {
            if (!window.socket) { // 先判断socket是否创建好
                return;
            }
            if (socket.readyState == WebSocket.OPEN) {
                // 通过socket发送消息
                socket.send(message);
            } else {
                alert("连接没有开启");
            }
        }

    } else {
        alert("当前浏览器不支持websocket");
    }
</script>
</body>
</html>